This is one of my biggest gripes about new Opera either. I can understand that such behavior would kill many scripting gimmicks (and new ads display), but for some sites speed penalty [of previous page reloading] is really distracting - and for some script-loaden pages you even can't see previous page in previous form anymore.

Unfortunately such functionality depends on rendering engine (I think) and Google/Chrome seems not being interested in increasing plain browsing speed. And - who presses back button anyway?